This invention relates to a therapeutic agent for the treatment of cancer which forms emboli in the vascular system surrounding the cancer lesion or tumor. The agent comprises an intravascular embolizing substance and an angiogenesis-inhibiting substance.
Embolization techniques have been utilized, especially for the treatment of inoperable or unresectable tumors. For example, embolization has been used to occlude the nutrient artery feeding the tumor, by administering an intravascular embolizing agent. Chemo-embolization techniques have also been utilized. In this case, anti-neoplastic agent in combination with an intravascular embolizing agent have been administered to maintain the concentration of the anti-neoplastic agent high in tumors or cancers.
As intravascular embolizing agents to be used for the above-mentioned purpose, there have been known degradable starch microspheres (DSM) (Cancer, 50, 631 (1982)), lipiodol (Cancer Res., 44, 2115 (1984), cross-linked collagen fibers (Cancer, 46, 14 (1980)), ethyl cellulose microcapsules (Cancer, 46, 14 (1980)), among others.
In these therapeutic methods, however, even the tumor-dominating artery is occluded, since the tumor regenerates by the formation of collateral artery caused by secretion of the tumor-induced angiogenesis factor, there is a fear that satisfactory cancer-suppressive effect would not be expected. Circumstances being such as above, the present inventors have tried to develop an intravascular embolizing agent containing an angiogenesis-inhibiting substance, which is capable of further improving the therapeutic effect by embolization.
The object of this invention is to provide an intravascular embolizing agent which is characterized by containing an angiogenesis-inhibiting substance and an intravascular embolizing substance, and is capable of enhancing cancer-suppressive effects caused by embolization. The present invention provides an intravascular embolizing agent to be administered singly or, in combination with an anti-neoplastic agent, which brings about stronger cancer-suppressive effects.
It has further been unexpectedly found that the cancer-suppressive effect could be enhanced by having an angiogenesis-inhibiting substance included in an intravascular embolizing agent, in a dosage less than that of single administration of an angiogenesis-inhibiting substance.